Question

Mixotrophic nutrition is present in
A. Navicula
B. Amoeba
C. Paramecium
D. Euglena

Answer 1

Hint: Mixotrophic organisms are the organism which performs more than one mode of nutrition. This mode of nutrition mainly is exhibited by kingdom Protista. Mixotrophic organisms use a mix of different sources of energy and carbon.

Complete answer:
Euglena belongs to the kingdom Protista and is a unicellular organism. Euglena performs both autotrophic and heterotrophic modes of nutrition. Most species of Euglena contain chloroplast which helps in autotrophic mode of nutrition by performing photosynthesis, however they can also take their nutrition heterotrophically just like animals. When sunlight is not present, Euglena derives its nutrition by another mode of nutrition known as saprophytic, osmotrophic or saprozoic. Euglena is an important organism for the environment because it is able to photosynthesize, so it can take carbon dioxide and release oxygen into the atmosphere.

Hence, the correct answer is option (D).

Additional information:
Protists are simple eukaryotic, unicellular organisms which are neither plants nor animals or fungi. Protists can also be found in colonies of cells. Most Protists are aquatic, damp terrestrial environments, or as parasites. All protists are not mixotrophs, some are strict heterotrophs. While a few protists are mixotrophs which are also called acetate flagellates. Mixotrophs can be found in both eukaryotes and in prokaryotes. In eukaryotes mixotrophs can be of two types, the one that has its own chloroplast and the second which obtains its chloroplast by kleptoplasty.

Based on efficiency mixotrophs are of three types-
Type 1 – Ideal mixotrophs
Type 2 – Phototrophic
Type 3 – Primary heterotrophic
Ideal mixotrophs use both prey and sunlight equally. Phototrophic activity is supplementary to consumption of food and if the prey is low then photographic activity can be seen.

Note: Among microorganisms, Paracoccus pantothropus is an example of mixotrophy and amongst plants. Mixotrophy is applicable to carnivores, hemi parasites and some myco-heterotrophic species.